The present invention relates generally to equipment utilized and operations performed in conjunction with subterranean wells and, in an embodiment described herein, more particularly provides a downhole ram pump.
A wide variety of downhole well tools may be utilized which are hydraulically operated. For example, flow control devices, packers, plugs, etc. are available, and others may be developed in the future, which use pressure in performing their respective functions.
In the past, the most common methods of supplying hydraulic pressure to well tools were use of well fluid pressure, and transmission of pressure through control lines extending large distances from a remote location, such as the earth's surface or another location in the well. However, well fluids usually contain debris which can cause a malfunction in a well tool, and pressure in a well fluctuates and is difficult to predict and control. Control lines are relatively expensive and time-consuming to install, and are subject to damage during installation.
Therefore, it may be seen that it would be very beneficial to be able to generate hydraulic pressure downhole, e.g., in relatively close proximity to a well tool which is operated using the pressure. This would preferably eliminate the need for using well fluid pressure to operate the well tool, and would preferably eliminate the need to extend control lines large distances in the well.